This invention relates generally to the papermaking process and more particularly to a new and novel suction roll/pressure roll combination and suction roll water removal system used in the papermaking process for removing water at for example the couch roll of the process. Because the present invention has particular but not exclusive application to couch rolls, the present invention will be primarily discussed and disclosed with respect to the couch roll art. The present invention has specific application in papermaking machines of the "Verti-Forma" and the "Papriformer" types.
In the earlier development of the art of papermaking, the forerunner of the modern papermaking machine was known as the Fourdrinier machine which was a generally horizontal papermaking machine having a headbox which delivered the liquid paper pulp stock onto traveling screen through a slice in the headbox. The traveling screens or wire were generally supported first by a breast roll and then by various primary and secondary forming boards which were the prime removers of water from the paper stock. After passing over suction boxes, the wire and the paper stock then passed over a couch roll which served to drive the wires in the Fourdriner machine and also to remove more moisture from the paper stock prior to its being sent to the web pressing and drying portion of the papermaking process. For a comprehensive review of the Fourdrinier machine reference should be made to Volume III of the three-volume work entitled "Pulp and Paper Manufacture" prepared under the direction of the Joint Textbook Committee of the paper industry and edited by Ronald G. MacDonald and published by McGraw-Hill Company, copyright 1970 and bearing the Library of Congress catalog card No. 68 -20994. The Fourdrinier papermaking machine is described in Chapter 6 of that volume starting on Page 245 and running through Page 295 with a detailed description of the couch roll being given on Page 286 and 287 of the same volume. As can be seen in FIG. 6-43 of that Volume on Page 287 the couch roll of a Fourdrinier machine generally comprises an outer shell which has a plurality of radial holes drilled therein with the holes being in contact with the inner portion of the couch roll which may be sectionalized to various vacuum or pressure sources.